The income summary is a temporary account used during the closing process at period end. All revenue accounts are closed into it, all expense accounts are closed into it, and the balance that remains — the period’s profit or loss — is then swept into retained earnings. Then the account returns to zero and waits for next year.
Why it exists at all
Revenues and expenses are temporary accounts: they measure a single period and must restart at zero. Retained earnings is permanent. The income summary is the staging area between them — it collects the whole period’s result in one place so a single, clean figure moves to equity, leaving a tidy audit trail of the close.
The three closing entries
- Close revenues: debit each revenue account, credit income summary — revenues now read zero.
- Close expenses: credit each expense account, debit income summary — expenses now read zero.
- Close the summary: whatever balance remains is net income (credit balance) or net loss (debit balance). Transfer it to retained earnings.
Worked example
A firm ends the year with $500,000 of revenue and $380,000 of expenses. Entry 1 credits income summary $500,000; entry 2 debits it $380,000; the account now holds a $120,000 credit — net income. Entry 3 debits income summary $120,000 and credits retained earnings $120,000. Every temporary account is zero, equity is updated, books are closed.
Modern reality
Accounting software performs this invisibly the moment you roll the year — many bookkeepers never see an income summary account on screen. It still matters to understand, because exam questions, older systems and audit walkthroughs all speak this language. The account it feeds appears in every Pro Forma Financial Statements projection, and its inputs are verified in a trial balance before closing begins.
Is income summary a permanent account?
No — it is the definition of temporary. It holds a balance only during the closing process and returns to zero immediately after.
Does income summary appear on financial statements?
No. It exists only in the ledger during closing; by the time statements are prepared, its balance has moved to retained earnings.
What does a debit balance in income summary mean?
Expenses exceeded revenues — a net loss for the period, which reduces retained earnings when closed.
Do dividends close through income summary?
No — dividends are not an expense. They close directly against retained earnings in a separate entry.